Topic: Oil pressure light on after highway speeds?

[MetalHead550]

Hey csendker.. Ha! Ha!  Its over with! Youre hooked!    See, you never would have learned all this great stuff if youd bought a brand new bike!
You have a great grasp on the theorem concerning your problems so now on to the hands-on right? 

The rich problem:  Id say youre rich due to the needle setting more so than the main jet.  I cant say from direct experience but what I understand is that running an aftermarket 4-1 will not affect your fuel mixture enough to need to rejet.  Pod filters definitly will, but not a replacement uni filter.  Besides both would make it leaner anyway so thats not the problem.

I would guess that someones been in those carbs before and mabey they decided to adjust the clip up to compensate for the 4-1 or perhaps they went ahead and rejetted?  Only one way to find out, but wait and see what a new filter does.  You may actually be running richer than you suspect since the temperatures in your area are pretty cool now.  Cold air leans the mixture some since its denser air.  Hot humid air does the opposite. 

If it were me Id find a set of 022A's that havnt been messed with.  Youve got all winter so just check ebay from time to time and theyre sure to show up.  You wouldnt have to mess with rejetting on those either.  Just clean/rebuild them and slap em on.

Id advise against that synthetic Rotella.  Find the normal 15w-30 that is formulated for fleet use.  Its not synthetic, and lacks the modifiers that automotive oil contains that can cause clutch slippage.  Actually do your own investigation, try a couple, and decide what YOU like best. 

Youre right about the pumps opporation.  But the theory about the oil running thin after extended high throttle is null in this case since as far as we know you are rich.  Runnin lean is what will cause overheating and the breakdown of oil viscosity.  Youll have to do as Twotired suggest and mark your throttle, then do a few plug chops.  Especially in the area that is causing the worst performance.  BTW 28 mpg is poor performance if you are running 3-4 grand in 5th gear.  Plenty of throttle left there.  Ive seen 27 mpg but that was after running 80-90 mph/7-8k rpm for an hour and a half!  Thats pushing it on a 550.  Later!

[csendker]

Hooked?  Yes, I sense this will get ugly. I'm resisting a heavy urge to tinker on a working machine.  That's why I want spare parts...

70 mph scared the hell out of me.  I can't imagine any faster.  I don't think I've had it much above 5K, ever.

Regular Rotella wasn't on the shelf, but Castrol was.  I'll head that direction for now.  Uni was ordered this AM.  Looking on e-bay for a set of spares 022A's; they typically don't indicate the carb model number though, just the bike model.

Needle clip: if I'm running rich, I move the clip up (away from the long pointy end-I don't know how they're mounted which would obviously impact 'up' & 'down')?  I've never seen one up close and personal, just diagrams. 

Again, thanks.

[Bob Wessner]

Needle clip: if I'm running rich, I move the clip up (away from the long pointy end-I don't know how they're mounted which would obviously impact 'up' & 'down')?

You've got it right. The needles slides down into the jet, so you have the orientation correct also.

[csendker]

I assume it's best to adjust one clip space at a time (all 4 at once).  And all 4 should be on the same clip space?

[Einyodeler]

This is the stuff on the shelf:

Shell Rotella T Synthetic 5W-40

http://www.shell-lubricants.com/products/pdf/RotellaTSynthetic.pdf

That`s what I use in all of my bikes, it has no clutch slipping anti friction additives.
You`ll notice a big difference in shifting and cold start up.

[Bob Wessner]

I assume it's best to adjust one clip space at a time (all 4 at once).  And all 4 should be on the same clip space?

Yes, typically you would do one clip postion at at time and check via plug chop(s) what the affect was. No, all four may not be in the same position when you are through tuning. There are a number of variables that come into play. One of the joys (did I say that?  ) of four cylinders, four carbs is the fine tuning you can do.

[Jonesy]

For higher performance machines, the inner 2 carbs will typically be tuned slightly richer to help keep the 2 inner cylinders cool. But, for a general-purpose get-around bike, they will be fine all the same.

[TwoTired]

I assume it's best to adjust one clip space at a time (all 4 at once).  And all 4 should be on the same clip space?

 No, all four may not be in the same position when you are through tuning. There are a number of variables that come into play.

I believe all four clips should be in the same position across the carb bank.  If your final tuning wound up otherwise, then there is something else going on with the engine/carbs as in mismatched or modified carb internal parts or cylinder valve timing and lift issues.  If you end up with the clips in different positions, you are masking a symptom of a problem elsewhere.
My opinion, anyway.

[dusterdude]

BUT,wouldnt a bike running pods perhaps benefit from differing needle positions or even different jetting.

[csendker]

I thought about pods, but went with the Uni direct drop-in replacement.  It seems to be the less radical modification from the factory set-up.  I figure if I'm running rich, I should fix that problem, not hide it with pods that flow more freely (leaner).  Besides, it seems to be that it would be a pain to pull the pods off for cleaning, at least harder than the drop-in would be.

Of course, after all of this, I'm still wondering why the oil light popped on (when at idle) after running hard for an hour.  I thought it was connected with the carb set-up, but that would only be if it was lean, not rich.  Can I be running rich at lower speeds and lean at higher speeds?  Maybe the needles are clipped too low while the main jets are gummed up?  The engine did seem to be running hotter than normal.

[MetalHead550]

Well, remember that fuel mixture is not governed by engine speed, but by throttle position.  But yes you can run rich at low/closed throttle and lean at high/open throttle, and vice versa.  You wont know for sure till you do plug chops though.  I still say yours is an over rich problem.  You were running no more than 70mph/ no more than 6k rpm which is between 1/2-3/4 throttle and got 28 mpg.  To me that says needle set too rich.

If it were the middle of summer and you were running old or too light weight oil, and you ran it at high rpms for a long while then came to an idle, I could see the oil pressure dropping enough to trip the sensor.  You would have thinned the oil at speed, heating it up, then caused the engine to become even hotter by setting at idle with no air flow to cool it after a hard run, plus your rpms would now be lower and the pump would not create as much pressure.  But since it was recently tuned up(Im assuming somewhat fresh oil), its cool out, and you really didnt run it that hard(these things will do 85 down interstate all day, no problem) thats not the case.  Unless you really are running lean.  But mabey if the pump is starting to go it would do the same thing at these temps.  Just run the correct weight oil in it, make sure the oil level is good, keep an eye on it but dont worry about it too much just yet.

[csendker]

Hmmmm.  It was the middle of summer, and warm out.  As I have not personally changed the oil, it very well may be old/too light/crappy/etc. In all the hubbabaloo of MSF school, getting the license, buying the bike, changing the title from CA to NY, tune-up, inspection,etc. I really don't know who did what.  That said, changing it is becoming #1 on the to-do list.  At least a new filter & good quality oil will put those possibilities to rest.  As I plan on doing all of the work on this myself from now on, at least over time I can be sure what has been done.

[Bob Wessner]

I guess I would have to agree the the clip postions should be in the same position on all four, all things being equal. Just didn't want to put it into the category of always and never since as these things get older with more miles, things change at a differing rates.

[KB02]

Of course, after all of this, I'm still wondering why the oil light popped on (when at idle) after running hard for an hour.

I have a 2000 Ducati Monster 750 that does the same thing from time to time on really warm days.  It doesn't stay on consistantly, but flickers a little bit at idle and goes away when I rev the engine. Most likely the fresh oil will help the situation go away. As for the running rich, like the others say, do the plug chops. That's the best way to see what's going on.

And don't worry about being scared at 70 mph. You'll get used to it...  

[L.A. Nomad........]

I had the same same problem! ( 1976 CB550K) I use to drive my bike to work everyday. My oil light would flicker on only after jumping off the freeway. Oil changed less than 1000 miles at that point. I used 10-40w oil and decided to change to 20-50 oil,which seemed to solve my problem. My oil was thinning out, but I didn't know why!

What I did different was I shut my gas valve off! I use to always leave it on "reserve"! I believe gas was mixing into the engine oil, thus breaking it down(thin oil). I now turn my valve off and never had the same problem again.  Hope it helps!

Nomad...........   

[Bob Wessner]

My oil light would flicker on only after jumping off the freeway.

According to the manual, flickering light after highway run in hot weather is not unusual. From my own experience, the pressure can drop to about 15 lbs at idle in hot weather.

[csendker]

Thanks for the info guys.  I have always shut the gas valve whenever I stop, so I don't think that's it.  I have a new oil filter & a gallon of Rotella 15W-40 (regular stuff) just waiting to be changed out.  I'm beginning to suspect I have old, crappy oil; but not for long.  Unfortunately, with 6" of snow last night, a test highway run in hot weather seems pretty far off.  Ugh.

[Bob Wessner]

Probably should have added, if it matters, also according the manual, assuming the oil pressure switch is functioning properly, the light is supposed to go out as soon as the oil pressure reaches 7-8 lbs. So, if it is flickering, you are flirting with this pressure level, but is still OK according to manual under hot idle conditions.

[TwoTired]

Probably should have added, if it matters, also according the manual, assuming the oil pressure switch is functioning properly, the light is supposed to go out as soon as the oil pressure reaches 7-8 lbs. So, if it is flickering, you are flirting with this pressure level, but is still OK according to manual under hot idle conditions.

Yes, the manual for the CB750 is just as you say.  But, there is no equivalent excerpt in the Shop Manual for the CB500/550.   The machines are different; wet sump/dry sump, different oil pumps, etc.

I have several Cb550s and have never seen the oil light flicker when idling.  Even on hot summer days in rush hour traffic with a high mileage (40-45K) bike I've had since 75.  Such an indication would concern me greatly.  Oil is engine life blood.  If I was using a good quality engine oil formulated for motorcycles, and saw the oil light flicker, I would discontinue operation until I found the cause and corrected it.

Of course, with multiple bikes, switching over to a "spare" is not much of a hardship, either.

[Bob Wessner]

Wasn't aware of the differences you pointed out. Thanks.

[csendker]

The light flickered just one day, and only when ideling after the one (and only) long high speed run.  Never before, never since.  The engine also seemed to be hotter than normal, and running rougher.  I would expect additional heat after 70 mph for an hour, but as a newbie, I don't have a reference as to how much is too much.  I was able to clear the oil light with a high idle (2k+), so I assumed the problem was (?)excessive heat(?) lowering the viscosity, thus lower pressure, thus light on.  Crank up the engine RPM, which spins the pump faster, which produces more pressure, or at least enough to clear the light.  I don't know the quality or age of the oil in it now, but I will be changing it soon to eliminate that potential.  As for testing whether or not this solves the problem, I'm going to have to wait a while (snow).

Sooooo, as is hasen't happened at any other time, I'm assuming the oil pump is OK.  That leaves me with either seriously crappy oil or an excessively hot engine. And the engine hasn't seemed too hot under any other driving conditions.  Hmmmmmmmmmm.......

[TwoTired]

As I've said, I have never seen the oil light come on regardless of how hot the my 550s have gotten.
I don't baby the bikes. Cruising at 70 or 80 MPH is routine.  And, I'm not at all shy of winding the engine to red line whenever I feel like it.  I have also used good quality oil.

If you are using oil that is straight grade, then it will indeed get thin when it gets hot.  Multigrade oil should behave as thicker oil when it gets hot and thiner when cold.  The additives in the oil allow this to happen as these have long chain molecules.  Excesive heat can destroy the long chain molecules.  And, the oil can also wear out from the meshing of the transmission gears chopping up the long chain additives.  Old or damaged multigrade oil will indeed behave as thin oil when it gets hot.  And, it can be expected the pressure be lower at idle because of this.

Damaged oil can also turn into sludge.  The sludge can deposit itself inside the engine, partially block the pickup screen, and restrict the flow through through the oil filter.  This could lower the oil pressure also.

Sludge can also deposit in the oil pressure sending unit, causing it to read falsely.

Poor quality oil can advance bearing wear and oil pump wear.  And, such wear can lower the oil pressure, also. 

My opinion is that the oil light is not something to ignore.  If it happened again after putting fresh good quality oil in there, it would warrant further investigation as to cause.

Good luck!

[MetalHead550]

Hey Lloyd, whats your opinion on using deisel fuel to flush out the engine every so often, durring an oil change of course.  I did this to an old Triumph that had been sitting for a while with old oil.  Drained the oil, closed the drain, filled with deisel, then kicked the engine over several times, with the ignition off obviously.  I also went through the gears a few times, worked the clutch, then sloshed the bjesus out of it and then drained it.  All kinds of crap came out.  Might help?

[TwoTired]

Clean is good, of course.  However, if there is sludge build up in the engine, solvents can loosen the deposits.  There is some risk that the oil pickup screen can become restricted and blocked, starving the engine of lubrication oil.

The use of detergent oils and frequent oil changes usually minimize build up.   But, a switch from non detergent to detergent oil has the same risk as using solvents in the crankcase; oil screen blockage.
Cheers,

[Jonesy]

TwoTired-

That happened to a friend who bought an old pickup truck. The owner never changed the oil regularly, so he filled it up with Castrol GTX. After a long drive down the highway, the oil light would come on. He stopped, checked the dip stick, the oil level was full. Hmmm... He started it back up, engine was OK. He got back on the freeway and it happened again. This happened a few times and he noticed when he got above a certain speed, the oil light would come on. When he dropped the pan, he found what you described- the GTX broke up all the sludge and when the engine really started moving the oil at higher speeds, the sludge chunks would be sucked up against the oil pickup, starving it. When the engine was shut off, the chunks would settle away from the pickup, and everything worked again.